Question

The formation of glucose from pyruvic acid derived from lactic acid, amino acids, or glycerol is called a. glycogenesis. b. glycogenolysis. c. glycolysis. d. gluconeogenesis.

Short answer

The formation of glucose from pyruvic acid derived from lactic acid, amino acids, or glycerol is called gluconeogenesis. Therefore, the correct answer is option d. \( \)

Step-by-step solution

Understand the given options

We have four choices to consider: a. glycogenesis b. glycogenolysis c. glycolysis d. gluconeogenesis

Analyze the terms

Understand the meaning of each term: a. Glycogenesis is the process of forming glycogen from glucose. b. Glycogenolysis is the breakdown of glycogen into glucose to be used as energy. c. Glycolysis is the metabolic pathway that breaks down glucose into pyruvate and releases energy. d. Gluconeogenesis is the formation of glucose from non-carbohydrate sources, such as lactic acid, amino acids, and glycerol.

Compare terms with the given exercise

The exercise asks for the formation of glucose from pyruvic acid derived from lactic acid, amino acids, or glycerol. Comparing the description of the terms we analyzed with the given condition, we can notice that gluconeogenesis is the process that occurs under such circumstances.

Select the correct option

Based on our analysis, the correct answer is: d. gluconeogenesis

Key concepts

Metabolic Pathways

Metabolic pathways are a series of chemical reactions occurring within a cell. These pathways orchestrate the complex biochemical processes necessary for life. Think of them as a map of reactions aimed to achieve specific cellular goals, like energy production or molecule synthesis.
There are two main types of metabolic pathways:

• Anabolic pathways: These require energy to build complex molecules from simpler ones. Examples include protein synthesis and glycogenesis.
• Catabolic pathways: These release energy by breaking down complex molecules into simpler ones. Glycolysis and glycogenolysis are catabolic pathways.

In essence, metabolic pathways are crucial to maintaining the balance between the building up (anabolism) and breaking down (catabolism) processes in our bodies. This balance ensures that cells have enough energy for growth, repair, and normal functioning. Understanding these pathways helps explain how carbohydrates, fats, and proteins are managed within the cell.

Glycogenesis

Glycogenesis is the process of converting glucose into glycogen for storage in the liver and muscle tissues. This is an example of an anabolic pathway, where energy is used to synthesize larger molecules. Glycogen acts as a storage form of glucose, which can be rapidly mobilized to meet sudden needs for glucose.
During glycogenesis:

• Glucose molecules are connected together to form long chains, resulting in glycogen.
• The enzyme glycogen synthase plays a key role in this assembly process.
• Energy, in the form of ATP, is utilized to build the glycogen chains.

This process is essential after meals when blood glucose levels rise. It helps manage blood sugar levels and ensures a reserve of energy for later use. Glycogenesis is crucial in maintaining the body's energy balance, particularly during fasting or between meals.

Glycolysis

Glycolysis is a catabolic pathway and the first step in the process of cellular respiration. It involves breaking down a glucose molecule into two molecules of pyruvate, producing a small amount of ATP and NADH in the process. Glycolysis occurs in the cytoplasm of the cell and does not require oxygen, making it an anaerobic process.
Key stages of glycolysis include:

• Energy investment phase: ATP molecules are used to convert glucose into a more chemically reactive form.
• Energy payoff phase: The energy-rich molecules ATP and NADH are produced as pyruvate is formed.

The overall net gain from glycolysis is 2 ATP and 2 NADH per glucose molecule. This process is fundamental because it provides immediate energy to cells and prepares glucose for further energy extraction in the mitochondria if oxygen is present. This step is crucial in both aerobic and anaerobic respiration pathways, highlighting its universal importance across different organisms.